Depending on use and storage arrangement would dictate what kind of cover you should purchase?
Sunbrella: Great all weather cover; however, it does shrink and fade over time and for extended outside stays in winter where's there's a chance for snow build-up or ice damming I wouldn't want it to be my first line of defense.IMHO one of the best fabrics for covers, if I could only purchase one.
Sharkhide: Is fair better suited for extended, wet or snowy climates; however, not as breathable as Sunbrella.
So, depending on use? I have both Sunbrella covers and treated with 303 fabric guard, holds-up very well to seasonal, summer rains. When I know it's going to be a rainy week, I use my full cover Sharkhide (also what I used as the cover for my Baja. Sheds water very well and has a decent ice dam rigidity, meaning the ice doesn't penetrate the fabric and then melt into the boat.
Be interested on other's experiences?
~Brett